Comparative study on different additives with a jet array on cooling of a hot steel surface

The current work aims to investigate the efficiency of a jet array in cooling of a hot steel plate having surface temperature above 900 °C. The entire study has been divided into two phases. The first phase consists of experiments which are aimed to optimize the jet array impingement height and the water flow rate. It has been found that the cooling rate is enhanced by 60% in case of a jet array compared to a single jet at the same water flow rate and impingement height. In both the single jet and the jet array used in the present work, free falling flow occurs under gravity. In the second phase, the effect of seven different additives on heat transfer performance during cooling has been studied at the optimized values of water flow rate and impingement height. Sodium Dodecyl Sulphate (SDS), Cetyltrimethyl Ammonium Bromide (CTAB) and Tween 20 have been used as surfactant additives, Polyvinylpyrrolidone (PVP) as a polymer additive, Titanium dioxide (TiO2), Cu-Al layered double hydroxide (LDH) and PVP dispersed in TiO2 have been used as nanofluid additives. The results indicate that a maximum cooling rate of 143 °C/s has been achieved for PVP based coolant which is 28% more than that obtained for pure water. The results also prove that ultrafast cooling can be attained by using additive based jet array impingement.